Plumb now planning hull??

Discussion in 'Boat Design' started by daaavo, Sep 1, 2019.

  1. tlouth7
    Joined: Jun 2013
    Posts: 100
    Likes: 25, Points: 28, Legacy Rep: 10
    Location: Cambridge, UK

    tlouth7 Senior Member

    A plumb "wave piercing" bow coupled to a planing after-body has been quite common in performance, monohull, sailing boats over the last few years (e.g. the VO70s). As mentioned this may be a function of maximising LWL within an LOA which is limited by the box rule.

    There is an argument however that this is a fast hull shape due to the reduction in pitching as the fore-body enters each wave. The disadvantage to that is the increase in water over the deck, which you can see from all the videos online is considerable. We see some production yachts which have plumb bows that are actually flared (such that the bow takes the form of a narrow triangular transom) in order to increase reserve buoyancy to allow the bow to lift over a wave. To my mind this negates the purpose of the plumb bow (except that it minimises LOA and so berthing fees, and achieves the desired look).

    A disadvantage of the hull shape described above is that it must transition quite rapidly from low volume, wave piercing fore-body to wide, flat, planing after-body which results in significant slamming in certain wave conditions. There are a couple of interviews with vendee globe skippers from previous editions of the race describing the punishing experience of sailing these yachts at speed.
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